This invention relates to systems used to power pneumatically operated tools. More particularly, this invention relates to systems of the above type for supplying a pressurized gas as a power source for such tools.
Pneumatic power sources are known which are utilized to provide a gas under pressure to a variety of pneumatically operated tools, such as screwdrivers, impact wrenches, air chisels, nailers and the like. Portable pneumatic power sources of the above type generally fall into one of two classes: devices consisting of a container for holding gas such as carbon dioxide under relatively high pressure and associated valving equipment; and devices having the container, valving equipment, and a small compressor operated by a motor, such as a diesel engine. Devices of the first class are typically constructed with relatively thick walls for the container in order to ensure against bursting of the container under the relatively high pressure of the gas stored therein, and are thus relatively heavy, which impairs their portability. Devices of the remaining class are typically mounted on a mobile cart which must be towed by an automotive vehicle, and are thus not truly portable but rather mobile. In addition, such devices require a fuel tank for containing the fuel used to power the motor or engine and thus cannot be used in some environments where the danger of explosion or fire is great. Further, when operating, the motor or engine produces noise and smoke which are at best inconvenient to passers by and at worst completely intolerable in certain environments.
In both classes of device, long pneumatic hoses are required in order to afford the necessary freedom of movement to the operator of the portable pneumatic hand tool to which the power source is connected. For example, when such power sources are used in conjunction with a pneumatic stapling tool for installing or replacing shingles on the roof of a structure, the connecting pneumatic hoses must be sufficiently long to permit the operator to climb a ladder and reach the most remote extremity of the roof. Hoses of such length, however, are extremely cumbersome to manipulate, particularly from a roof location, and thus impair the efficiency of the operator. Similar disadvantageous constraints apply with equal force to other applications of such pneumatic power sources.
Another disadvantage inherent in prior art pneumatic power sources resides in the fact that the working gas must be stored in the container at relatively high pressures in order to reduce the physical size of the container to a manageable size. This in turn requires a pressure regulator between the container and the pneumatic tool, which is designed to operate at a relatively low pressure, e.g. 100 psig. Such pressure regulators have been known to fail on not infrequent occasions, with the result that the companion tool is damaged or destroyed, sometimes with injury resulting to the operator.
Efforts in the past to devise a portable pneumatic power source devoid of the above limitations or disadvantages have not been successful to date.